Bishler-Napieralski reaction

This method is remarkably useful for the synthesis of some phthalide alkaloids which have been hitherto prepared by the Bishler-Napieralsky reaction. Condrastine I and II54, for instance, have been prepared from 2-methyl-3,4-dihydro-6,7-dimethoxy-isoquinolinium iodide 52 and 3-bromomeconine 53 in the total yield of 77% (ratio I II = 42 35) 38). 

The Bishler-Napieralski reaction, described above, is a named reaction in which Vilsmeier formylation results in a molecule that can participate in a subsequent cyclization reaction, resulting in a net annulation. There are numerous other examples of similar tandem sequences, most of which are not named reactions, and they generally give only modest yields. For instance, when ketone 25 is treated with a Vilsmeier reagent, isoflavone 26 is produced in nearly quantitative yield. ... 

---